The AIE behaviors of two D-π-A type imidazolium-based compounds 4a and 4b have been studied. 4a is a typical AIE-active molecule, whereas 4b is not. The experimental and computational work demonstrates that the AIE effect mainly depends on the restricted rotation of imidazolium unit (electron acceptor, A) in aggregate state, rather than TPA group (electron donor, D).

中文翻译：

---

通过逐步改变可旋转部分，了解D-π-A型咪唑鎓类化合物的聚集诱导发射（AIE）效应的细节

研究了两种D-π-A型咪唑基化合物4a和4b的AIE行为。4a是典型的AIE活性分子，而4b不是。实验和计算工作表明，AIE效应主要取决于咪唑鎓单元（电子受体，A）在聚集状态下的受限旋转，而不是TPA组（电子供体，D）。